THE MICROSCOPE AND ITS PARTS. 
17 
Leaving aside accuracy of fittings as an attribute of 
every good stand, let us consider the matter of steadi¬ 
ness. The two leading types of microscopes, so far as 
the base is concerned, are those on the “ horseshoe ” 
foot and those on a tripod foot. Stands on the 
former base are moderately steady when the optic 
tube is vertical, but even in this position they are 
not difficult to overset. When the tube is put to the 
horizontal position they are very far from steady; 
the least push will overturn them, and the least tremor 
affects them seriously. The horseshoe base is not the 
base for photo-micrography, and we cannot but wonder 
at some of the first Continental makers persisting in 
making this base alone, and still more at their recom¬ 
mending it for this purpose. Infinitely superior for our 
purpose, to say nothing of general considerations, is 
the tripod base, the tripod having as wide a “ straddle” 
as convenient. 
Again, it will be seen, on examining most of the 
Continental models, that the optic tube is supported and 
works on a very short body or “ limb.” Some of the 
best-known models have this support only about three 
inches long. The body on which the tube, actuated by 
the coarse adjustment, moves, should, for the sake of 
steadiness, be as long as possible. Let the reader 
compare the short limb of a Zeiss stand for photo¬ 
micrography with that of the stand figured No. 1. 
The calibre of the tube is often too small; it should 
not be less than i\ inch, especially for work without 
the ocular. Still again it may be observed that many 
